Sleep Part 2: Sleep and Pain

By Kendall Wisehart DPT, ATC

In my last blog about sleep, I reviewed how much you should sleep and why. In that post, we reviewed the critical role sleep plays in the brain’s function and total systemic regulation and what < 7 hours of sleep may lead to long term. This week’s post, and part two on the topic of sleep, will focus specifically on sleep and pain.

Superficially, if you were to ask someone off the street what a physical therapists primarily treats, they will tell you it’s pain. By and large, they wouldn’t be wrong. Both pain and sleep disorders are highly prevalent and persistent conditions in the population and understanding the link between the two is important in guiding treatment. It is widely accepted that the relationship between sleep and pain is bidirectional, causality is hard to determine (Siversten, et. Al., 2015).

Every year the National Sleep Foundation collects data about sleep in America and this year’s topic of interest was ‘sleep and pain’. Overall, the data suggested that pain is associated with the feeling of not getting enough sleep. Up to 64% of people without pain said they got enough sleep, while only 46% of people with acute pain and 36% of people with chronic pain said they got enough sleep. People who reported inadequate sleep also described negative impacts on their mood, quality of life, relationships, work productivity and other activities of daily living. (Knuston, 2015). In other words, pain may be associated with a 20-30% likelihood of not getting enough sleep.

Looking deeper down the rabbit hole, we know that chronic pain conditions are known to have high degrees of central sensitization or, in other words, central pain processing mechanisms that contribute to the increased perception and perpetuation of pain. While the scope of this blog won’t cover important concepts in modern pain science and perception of pain, it’s important to understand that a key characteristic of central sensitization syndromes is heightened pain sensitivity or lower thresholds for the perception of pain. Basically, a pin prick (low pain stimulus) will cause a pain response (lower threshold) when it otherwise would not.

Whether you’re recovering from an injury or not, it is important to make sleep a priority in your life. Research suggests that sleep deprivation is associated with disturbances in descending pain inhibitory control mechanisms and results in increased pain sensitivity. Just being in pain, acute or chronic, is associated with inadequate amounts of sleep – thus, further increasing pain sensitivity. Sleep hygiene or routine habits to prepare you for a restful night are important in establishing a healthy sleep cycle. Sleep quality is a strong predictor of next-day pain sensitivity.  Improvements in sleep often proceed and predict improvements in pain (Koffel, et al., 2015). Therefore, focusing on sleep should be a priority to any rehabilitation program.

In short, we are a summary of our habits. If we don’t practice healthy sleep hygiene and ignore our internal drive to sleep by staring at a computer screen well into the night, our ability to recover from everyday stresses decreases. In a vacuum, without the stress of modern life, nearly every tissue has the capacity to recover and heal. The only treatment needed is sleep. Our job as physical therapists is to create an environment that this healing can happen in the midst of everyday stress.